1. Field of the Invention
The present invention relates to an electronic typewriter.
2. Description of the Related Art
Recording apparatuses installed in an electronic typewriter and which perform recording on a recording medium such as paper, transparent films for over head projectors, or the like (these are called "recording paper", or simply "paper" hereinafter) are proposed in a number of forms that mount various types of recording heads. For example, recording heads such as wire dot heads, thermal heads, ink jet heads, are used in serial printers. In particular, ink jet printers are attractive owing to their low running cost, low operating noise, high speed recording and high resolution recording resulting from the fact that they eject ink directly onto recording paper.
Today, ink jet recording apparatuses, and in particular, recording heads, are fabricated by the film-forming technique or micro-processing technique used for manufacturing semiconductor devices. As a result, fabrication of small-sized and inexpensive recording heads is being implemented, and removable type recording heads, which include an ink reservoir as their integral part, are proposed. This also makes it possible to produce recording apparatuses of small-sized, simple construction.
The ink jet recording apparatuses having these various advantages are being widely used as recording devices of such apparatuses as electronic typewriters, word processors, facsimiles, copying machines, or the like. The ink jet recording apparatuses are provided with arrangements suitable for functions and operation types of each of these apparatuses.
The following functions must be considered with regard to electronic typewriters.
On typewriters, in general, position setting or designating operations of a recording head are often performed by moving the recording head along recording paper on a platen. For example, operations for determining a layout by using such functions as right or left margin settings, tab settings, operations for setting record position on formatted paper are executed by moving the recording head along the recording paper so that the recording head is positioned at a desired position.
In an electronic typewriter to which the ink jet recording apparatus is applied, when such operations take a long time, the ink inside ink ejection outlets will increase its viscosity because the ink ejection outlets of the ink jet recording head are exposed to air without being driven, and hence the solvent of the ink vaporizes from the ink-ejection outlets. Such increase in the viscosity of the ink will cause deterioration of the printing quality, or in extreme case, ejection failure because the ink ejection characteristic of the ink jet recording head greatly depends on the viscosity of the ink.